Motor vehicle rack and pinion power steering gears typically include a pinion gear rotatably supported on a housing and a rack bar supported on the housing for bodily movement generally perpendicular to the pinion gear. Gear teeth on the pinion gear mesh with rack gear teeth on the rack bar to shift the rack bar back and forth when the pinion gear rotates.
In the rack and pinion power steering gears described in U.S. Pat. Nos. 4,454,801 and 4,788,877, issued 19 Jun. 1984 and 6 Dec. 1988 and assigned to the assignee of this invent referred to as a pinion head, includes a spindle at one end and an annular skirt at the other end having an outer cylindrical surface. A ball bearing between the steering gear housing and the spindle cooperates with a sleeve bearing on the housing around the outer cylindrical surface of the skin in rotatably supporting the pinion head on the housing. To minimize the overall size of the steering gear and to minimize the unsupported span of the pinion gear, the ball bearing is closely adjacent a first end of the pinion gear and the outer cylindrical surface on the skin terminates at an annular shoulder closely adjacent a second end of pinion gear. In this construction, the pinion gear teeth are formed by a rolling process. Hobbing, a gear tooth forming process yielding gear teeth of improved quality, requires more clearance between the second end of the pinion gear and the annular shoulder on the skin than is available in this construction and, therefore, cannot be used without increasing the length of the pinion head and the unsupported span of the pinion gear.